Young American punk rockers are besieged and beset by Nazi skinheads when they accidentally witness a murder in a grungy backwoods bar of the ‘no Jews allowed’ variety. Barricading themselves away in the bar’s titular green room, the kids are forced into the fight of (or for) their life as their inadvertent Nazi captors attempt to shut them up for good.

Jeremy Saulnier’s latest is a more conventional type of horror film than his previous MurderParty or BlueRuin, but is no less exciting for it. A brutal, vicious siege movie in the tradition of Assault on Precinct 13 and From Dusk Till Dawn, it makes up for what it lacks in originality with style and heart. That, and the presence of one Patrick Stewart, Knight of the Realm, national treasure, starship captain and, as it happens, sinister bar owner. Stewart plays proprietor and Nazi chief Darcy Banker, a mode of villainy we’ve not really seen from him since his performance in Conspiracy Theory in the nineties. Calm, genial and utterly terrifying, Patrick Stewart utterly owns every minute his relatively short time in Green Room, making this Nazi monster an oddly compelling and charismatic proposition.

The kids too, are alright. Anton Yelchin has made a career of playing awkward yet sympathetic nice guys, and GreenRoomoffers him that opportunity yet again. As Pat, he undergoes a familiar zero-to-action-hero arc reminiscent of Doug’s journey in The Hills Have Eyes (specifically the remake), allowing the film its few cathartic beats. He’s surrounded by a pretty young cast which also includes Imogen Poots and Alia Shawkat among its non-Nazi victims. The inherent likeability of that cast allows Saulnier to concentrate on the action and the violence, not needing to flesh them out much more beyond the archetypes they obviously are. The casting of Shawkat is particularly affecting, her young looks, doe eyes and ArrestedDevelopment hangover making scenes of her peril even harder to watch than they already are. And Green Roomis plenty cruel, letting us come to like these kids just enough for it to hurt when they are sliced at with machetes, blasted at with double-barrelled shotguns and chomped to bits by slathering attack dogs.

Thankfully, there’s a recurrent streak of black humour which stops Green Roomfrom getting too bogged down in the misery and emotional (plus very physical) torture, not the least one recurrent gag which earns the film a deep belly laugh, right at the best possible moment. The action works well too, the kids fighting back with a degree of realism which helps keep the last act grounded in spite of itself.

Saulnier is batting three for three with Green Room. While it feels more conventional and less unpredictable than his previous movies, it is his slickest and most exciting yet. It’s brutal, gory action horror with a spitting, fighting punk spirit. And Patrick Stewart too.